Field of the Invention
The present invention relates to the automatic transmission of a vehicle.
Description of the Related Art
As an automatic transmission, a so-called dual clutch transmission is known. The dual clutch transmission includes two transmission mechanisms that implement different gear ratios, and connects/disconnects the two transmission mechanisms to/from a driving source such as an internal combustion engine, thereby suppressing interruption of power transmission to the drive wheels at the time of gear change. A transmission that maintains the stop state of a vehicle using interlock of the transmission is also known. Japanese Patent No. 5081215 discloses, in a dual clutch transmission, intentionally putting the vehicle in two speed gears for parking lock, thereby interlocking the transmission to maintain the stop state of a vehicle.
Depending on an arrangement of a transmission, interlock may occur when the vehicle reaches a special traveling state. In such a case, it may be difficult to immediately cancel the interlock due to a jam in an engagement mechanism or the like. Since functions of the vehicle are partially lost upon interlock generation, generation of unintended interlock needs to be prevented.